Electrosurgical gas attachment

ABSTRACT

A nozzle and electrode combination for use with an electrosurgical device is described. The nozzle includes a shroud defining a channel and a lumen which intersect to define an acute angle. An electrode is positioned within the channel and includes a distal end extending from a distal portion of the shroud and a proximal end extending from the proximal portion of the shroud. An end cap positioned adjacent the proximal portion of the shroud about the electrode is preferably overmolded to the shroud and the electrode. Preferably, a portion of the walls defining the channel and/or the lumen include conductive material which communicates with the electrode to eliminate electric potential within the shroud.

RELATED APPLICATIONS

[0001] This application is a Continuation of U.S. patent applicationSer. No. 09/712,538 filed on Nov. 14, 2000, which is a Continuation ofU.S. patent application Ser. No. 08/621,151 filed on Mar. 21, 1996, theentire contents each are incorporated herein by reference.

BACKGROUND OF THE INVENTION

[0002] This invention relates to a nozzle and electrode combination andmethod of manufacturing a gas seal therebetween and specifically theinjection and over molding of a shroud and end cap to the electrode.

BACKGROUND OF THE DISCLOSURE

[0003] U.S. Pat. No. 3,595,239 has a catheter with a removable axialelectrode and a proximal side port to receive fluid to inflate thecatheter tube. Inert gas, such as argon, delivered concurrently withelectrosurgical energy forms an ionized path for energy flow from anelectrode in the distal end of the electrosurgical pencil. Commerciallyavailable gas electrosurgical pencils are made specially for controlleddelivery of argon and electrosurgical energy delivery. Gas surgicalpencils have a pair of switches that start and stop argon flow asdisclosed in U.S. Pat. Nos. 5,217,457; U.S. Pat. No. 5,244,462 and U.S.Pat. No. 5,088,997 all assigned to the same assignee as this disclosure.The switch for directing argon flow mounts on the electrosurgicalpencil. A gas line for argon and a pair of switches for theelectrosurgical generator coagulation or cut wave forms are on thepencil. The argon electrosurgical pencil includes an electrical cablewith wires for connection directly to the gas surgical unit to triggerthe flow of argon gas when the electrosurgical energy is called for bythe surgeon. The gas delivery control is on the pencil and controls thegas delivery from the separate on and off switch buttons and wiresconnecting to circuits integral with the gas surgical unit. In additionto the three wires connected between the argon electrosurgical penciland the gas surgical unit, there is another wire for providingelectrosurgical energy from the electrosurgical generator. Cut andcoagulation wave forms are controlled by buttons therefor on the gassurgical pencil.

[0004] A standard electrosurgical pencil without argon gas plumbing oran extra wire is made in high volume and cost about half of that for anargon electrosurgical pencil. Adapting a standard pencil to operate thegas surgical unit offers lower cost to practitioners that have neverused argon with electrosurgery and to those who infrequently use argonelectrosurgery due to added cost.

[0005] U.S. Pat. No. 4,781,175 has an argon electrosurgical pencil witha sensing lumen to determine the proper operation of the pencil byreturn of gas to the delivery apparatus thus verifying a properconnection and flow of the gas at the nozzle. Thus, the gas deliveryapparatus responds accordingly.

[0006] U.S. Pat. No. 5,324,283 has a switch on an endoscope. The switchbreaks a light path through optic fibers to control external accessoriesremotely turned on and off. U.S. Pat. No. 4,209,018 has a tissuecoagulation apparatus with indicating means in circuit with the activeand return electrode leads. An output signal from the indicating meansprovides information to a control for the electrosurgical generator. Thespecific indicating means can respond to various physical values showingthe presence and strength of an electrical arc between the distal endsof bipolar electrodes. The device controls the strength of the arc soheat applied during electrosurgery is minimized to avoid tissue cellrupture and/or burning of albumin. The monitoring function provided bythe indicating means controls internal circuitry within theelectrosurgical generator by means of wiring directly to the generator.There is no teaching of the indicating means controlling somethingexternal of the generator such as the argon delivery from a gas surgicalunit. The electrically connected (hard wired) indicating means is merelyexternal pickup for the control and does not have an external output foranother device such as a gas surgical unit.

[0007] Any number of internal inductive pickups has been proposed andused for control of RF leakage. U.S. Pat. No. 5,152,762 discloses aninductive pickup and references prior patents that use a winding on acommon magnetic core about which the active and return leads are alsowound. When there is an unbalanced between the flow of current throughthe active and return leads an EMF is generated in the extra winding.That EMF is used as a signal to control the RF leakage and maintainbalanced flow of energy in the active and return leads. Inductive coilsfor leakage are internal with respect to the electrosurgical generatorand as such precede the output connections on the exterior of thegenerator. They are sensitive to inductive differences in the active andreturn leads, but provide no external signal for use with an accessory.

[0008] U.S. Pat. No. 5,160,334 has an electrosurgical generator andsuction apparatus with a switching circuit connected to a hand switch orfoot switch to operate the electrosurgical generator remotely. Theswitching circuit activates a controller for a vacuum motor plumbed toremove the smoke that results at the site of the electrosurgery. Clearlythe remote operation of the switching circuit for the smoke evacuator bythe hand or foot switch is hard wired, i.e., passes through internalwires in the electrosurgical unit. This approach as well as thosedescribed are disadvantageous to the many of existing electrosurgicalgenerators presently in operation in hospitals throughout the world. Theinternal wiring for automatic activation of the suction or the likeaccessory is required in the electrosurgical generator. It is desired tobe able to have an automatic activation that easily starts and stops theargon gas flow and is external to the electrosurgical generator, gassurgical unit and the standard of electrosurgical pencil.

[0009] U.S. Pat. No. 5,108,389 discloses an automatic activation circuitfor a smoke evacuator used with a laser. A foot switch breaks a laserbeam and signals for operating the smoke evacuator. There is no physicalassociation or direct electrical coupling or attachment between thelaser and the smoke evacuator. That is to say that, when the laser beamis transmitted and received and the foot switch interrupts the laserbeam the control signal comes from the foot switch not the laser.

[0010] U.S. Pat. No. 5,041,110 discloses a cart for supporting anelectrosurgical generator, gas supply with automatic valves and acontrol logic panel. This cart adapts the many different existingelectrosurgical generators for use with argon gas. While the term,“electrosurgical pencil” is repeatedly referred to throughout the '110patent, the disclosure therein is made only to a special gaselectrosurgical pencil. In particular, a gas tube connects to the pencilto supply the inert argon through a passage in the pencil hand piece andabout a wire carrying the electrosurgical energy. There is no switchcontrol on the pencil and no suggestion of how a standard pencil couldbe used. Moreover, the activation of the combined gas tube and specialelectrosurgical pencil is merely by a foot switch. The control logicpanel is electrically connected to the gas flow control valve assemblyand the electrosurgical generator for the control of gas flow andelectrosurgical energy from the foot switch.

[0011] There remains a need to be able to adapt the inexpensive standardelectrosurgical pencil for activation of the argon flow from a gassurgical unit. Readily available, inexpensive and high volumeelectrosurgical pencil thus can be used to start and stop the flow ofargon during electrosurgery. The circuit disclosed responds to thesurgeon's request for electrosurgery made at the electrosurgical pencilcut or coagulation buttons. The circuit concurrently delivers argon to aspecial gas electrode fit to the distal end of a standardelectrosurgical pencil. The special gas electrode is the subject of U.S.application Ser. No. 08/619,380 titled “Circuit And Method For ArgonActivation”, filed Mar. 21, 1996 and is assigned to the same assignee.The references noted herein are incorporated by reference and made apart of this disclosure.

SUMMARY OF THE INVENTION

[0012] A circuit for concurrent activation of a gas surgical unit flowcontrol valve and an electrosurgical generator upon the surgeon'soperation of an electrosurgical energy request button on anelectrosurgical pencil is disclosed. The circuit preferably has anautomatic switch connected to receive current flow when the energyrequest button is operated by the surgeon. The automatic switch opens orcloses when the energy request button is opened or closed respectivelyby the surgeon. The automatic switch connects to the gas surgical unitflow control valve and operates it to send inert gas to theelectrosurgical pencil. The automatic switch connects to theelectrosurgical generator, operates it and delivers selectivelyelectrosurgical energy to the electrosurgical pencil.

[0013] The circuit responds if the surgeon uses the electrosurgicalenergy request button on the electrosurgical pencil to obtain a cut waveform or a coagulation wave form from the electrosurgical generator.

[0014] An electrode and nozzle combination preferably transportsionizable gas to a tip on an electrosurgical instrument for gas enhancedelectrosurgery by a surgeon on a patient. An electrode in the preferredembodiment has a proximal end, a distal end, and a length therebetween.The length may be substantially along an axis A. A shroud mostpreferably surrounds the electrode along its length leaving the proximaland distal ends of the electrode exposed. A patient part on the shroudpreferably points toward or faces the patient. A rear part on the shroudpreferably points toward the rear or the pencil that the surgeon wouldhold. The patient and rear parts in the preferred embodiment alignsubstantially along axis A. A passage between the patient part and therear part might define a space within the shroud and about the length.At least one port in the shroud may contain a lumen protruding from theshroud toward the proximal end at an angle to the axis A. The lumenpreferably connects with the passage for fluid communicationtherebetween.

[0015] An end cap in the preferred embodiment attaches to the proximalend for surrounding the electrode and for forming a gas tight sealbetween the proximal end and the rear part of the shroud. Acomplimentary portion on the rear part and an anti rotation lock on theend cap most preferably engage to prevent relative rotary motiontherebetween. The anti rotation lock and the complimentary portion eachhave, in the preferred embodiment, hexagonal conjugating featuresthereon. An anti twist posterior on the end cap is preferably shaped tointerengage with the electrosurgical pencil to prevent relative rotationtherebetween. The anti twist posterior and the electrosurgical pencileach may have hexagonal interengaging features thereon.

[0016] The shroud and end cap are in the preferred structure polymersthat can be injection and overmolded, respectively about and then to theelectrode for forming a gas tight seal of the rear part of the passageand at the proximal end. The angle between the lumen and the axis Amight be acute so the port is approximately adjacent the end cap. Theshroud may be injection molded and the end cap could be overmolded tothe shroud and the electrode proximal end. The passage might then besubstantially along axis A and coaxial with respect to the length. Arecess on the rear part could receive thereover and therewithin aprojection on the end cap formed during molding.

[0017] A method of manufacturing a gas tight seal between a shroud andan electrode may be by injection molding the shroud. The shroud may bemade with the passage therethrough, the patient part pointed toward thepatient and the rear part pointed aft. The shroud is preferablyinjection molded with at least one port containing the lumen protrudingtherefrom toward the proximal end at an acute angle to the passage sothe lumen and the passage may connect for fluid communication. Fixturingthe electrode within the passage without contact between the shroud andthe electrode is a preferred step of the method. Another step that ispreferred may include overmolding the end cap to the shroud forattaching the electrode and to form the gas tight seal with the proximalend near the rear part of the shroud.

[0018] The method of manufacturing the gas tight seal between the shroudand the electrode might have the step of fixturing the electrodesubstantial coaxial within the passage and with the electrode tipextending from the patient part. The method of manufacturing couldinclude the step of overmolding the electrode for forming the end capbetween the shroud and the electrode at the rear part while theelectrode is fixtured.

BRIEF DESCRIPTION OF THE DRAWINGS

[0019]FIG. 1 is a schematic perspective view of a system having a gassurgical unit flow control valve and an electrosurgical generatorconcurrently activated upon the surgeon's operation of anelectrosurgical energy request button on an electrosurgical pencil.

[0020]FIG. 2 is a side view in cross section taken along line 2-2 ofFIG. 1 for showing the relative coaxial relationship of the electrodeand the shroud in the nozzle and electrode combination.

[0021]FIG. 3 is an exploded view of the shroud, electrode and end cap aswould be seen from the pencil end of the nozzle and electrodecombination.

[0022]FIG. 4 is a side view in cross section taken along line 2-2 ofFIG. 1 for showing an alternate shroud in the nozzle the relativecoaxial relationship of the electrode and the shroud in the nozzle andelectrode combination.

DETAILED DESCRIPTION OF THE INVENTION

[0023] A circuit 10 for the system for concurrent activation of a gassurgical unit flow control valve and an electrosurgical generator 11upon the surgeon's operation of an electrosurgical energy request button12 on an electrosurgical pencil 13 is disclosed in FIG. 1. The circuit10 has an electrosurgical pencil 13 such as E2502B, E2515, E2516, E2525,E2550 manufactured by Valleylab of Boulder, Colo. and for supplyingpower in the circuit 10 a nine volt battery activates an automaticswitch to provide simultaneous flow of electrosurgical energy from theelectrosurgical generator 11 and flow of inert gas from the gas surgicalunit flow control valve 15 in FIG. 1. An automatic switch 16 receivesthe flow of current upon the operation of the energy request button 12by the surgeon. The automatic switch 16 opens or closes when the energyrequest button 12 is opened or closed, respectively by the surgeon. Theautomatic switch 16, which is connected to the gas surgical unit flowcontrol valve 15, operates control valve 15 to send inert gas to theelectrosurgical pencil 13. The automatic switch 16 is connected to theelectrosurgical generator 11 and operates to selectively deliverelectrosurgical energy to the electrosurgical pencil 13.

[0024] The circuit 10 responds if the surgeon uses the electrosurgicalenergy request button 12 on the electrosurgical pencil 13 to obtain acut wave form or a coagulation wave form from the electrosurgicalgenerator 11. Standard electrosurgical pencils such as those mentionedherein include two separate switch buttons 17 and 18, one for cuttingand another for coagulating.

[0025] The gas surgical unit flow control valve 15 of FIG. 1 has tubingshown connected to the electrosurgical pencil 13. The delivery of anionizable gas such as argon is the subject of this disclosure and inparticular, the manifolding of the gas to the electrode of theelectrosurgical pencil 13 during enhanced electrosurgery. Automaticswitch 16 is located between electrosurgical pencil 13 and the gassurgical unit 26. The preferred gas surgical unit is made by Valleylabof Boulder, Colo. as the GSU or Force Argon unit. The three connectionsshown in FIG. 1 activate the gas control valve 15 for cut orcoagulation. With regard to the latter, the connections pass through thegas surgical unit 26 and connect via a foot switch terminal (not shown)to the electrosurgical generator 11. In FIG. 1 the gas control valve 15is shown schematically. Skilled artisans will understand that suchvalves are electrically activated, for example by solenoid, to start andstop gas flow. A convenient form of the circuit 10 is thus shown as abox in FIG. 1. In that box the components of circuit 10 are provided.

[0026] An electrode and nozzle combination 30 for transporting ionizablegas to a tip 31 on an electrosurgical instrument for gas enhancedelectrosurgery by a surgeon on a patient is shown in FIGS. 1, 2, 3 and4. An electrode 32 has a proximal end 33, a distal end 34, and anintermediate portion having a length 35 therebetween that issubstantially along an axis A as best shown in the side view of FIGS. 2and 4 and the exploded view of FIG. 3. A shroud 36 surrounds theintermediate portion of electrode 32 along its length 35 and leaves theproximal and distal ends 33 and 34 of the electrode exposed. A patientpart or distal portion 37 of the shroud 36 points toward or faces thepatient (not shown). A rear part or proximal portion 38 of the shroud 36points toward the rear of the pencil that the surgeon would hold. Thedistal and proximal portions 37 and 38 of shroud 36 are substantiallyaligned along axis A. A passage or channel 39 between the distal portion37 and proximal portion 38 defines a space 40 within the shroud 36 whichis about equal in length to the length 35 as best depicted in FIG. 2. Atleast one port 41 in the shroud 36 defines a lumen 42 which extends fromthe shroud 36 toward the proximal end 33 of electrode 32 at an angle tothe axis A in FIG. 4. The lumen 42 connects with the passage 39 forfluid communication therebetween as seen in FIGS. 2 and 4. In analternate embodiment shown in FIG. 4, a conductive coating 49 is formedon the inside wall of shroud 36 and port 41 and connects electricallynear the end cap 43 to the electrode 32 for eliminating the electricalpotential in the gas carrying space 39 and 40 therewithin. Nozzle 30shown in FIG. 2 has another way of insulating to protect the surgeon.Specifically, the port 41 includes a connector 41 a and a highdielectric tube, preferably formed of silicone.

[0027] An end cap 43 is attached to the proximal end 33 of the electrode32 and forms a gas tight seal between the proximal end 33 and theproximal portion 38 of the shroud 36. A complimentary portion 44 isprovided on the proximal portion 38 of shroud 36 and an anti rotationlock 45, i.e., hex head, is provided on the end cap 43 for engaging thecomplimentary portion 44 to prevent relative rotary motion therebetweenas best illustrated in the exploded view of FIG. 3. The anti rotationlock 45 and the complimentary portion 44 each have hexagonal conjugatingfeatures thereon. An anti twist posterior 46 on the end cap 43 shaped tointerengage with the electrosurgical pencil 13 prevents relativerotation therebetween. The anti twist posterior 46 and theelectrosurgical pencil 13 also have hexagonal interengaging featuresthereon in the preferred embodiment.

[0028] The shroud 36 and end cap 43 are formed of polymers that can beinjection and overmolded, respectively to the electrode 32 for forming agas tight seal for the passage 39 about the proximal end 33 of electrode32 and with the proximal portion 38. The angle between the longitudinalaxis of the lumen 42 and the axis A is acute and is preferably about12.6 degrees but may be in the range of 10 to 20 degrees. The proximalend of port 41 is positioned approximately adjacent the end cap 43 asseen in FIGS. 2 and 3. The shroud 36 is injection molded and the end cap43 is overmolded to the shroud 36 and the electrode 32 at proximal end33. A recess 47 in FIG. 3 on the proximal portion 38 of shroud 36receives thereover and therewithin a projection on the end cap 43 formedduring molding as seen in cross section in FIG. 2.

[0029] A method of manufacturing a gas tight seal between shroud 36 andelectrode 32 includes injection molding the shroud 36. The shroud 36 isinjection molded with passage 39 therethrough, the distal end 37 pointedtoward the patient and proximal portion 38 pointed aft. The shroud 36 isinjection molded with at least one port 41 containing lumen 42protruding therefrom toward the proximal end 38 at an acute angle to thepassage 39 so the lumen 42 and the passage 39 connect for fluidcommunication. Fixturing the electrode 32 within the passage 39 withoutcontact between the shroud 36 and the electrode 32 is a step of themethod. Another step is overmolding end cap 43 to the shroud 36 forattaching the electrode 32 and to form the gas tight seal in the rearpart 38 of the shroud 36.

[0030] The method of manufacturing the gas tight seal between the shroud36 and the electrode 32 has the step of fixturing the electrode 32substantial coaxial within the passage 39 and with the electrode tip 31extending from the distal portion 37 of shroud 36. The method ofmanufacturing includes the step of overmolding the electrode 32 forforming the end cap 43 between the shroud 36 and the electrode 32 at theproximal portion 38 while the electrode 32 is fixtured.

[0031] An electrode and nozzle combination 30 and method of manufacturethereof have been disclosed with specificity. Skilled artisans couldsubstitute other components and method steps and achieve similarbenefits and advantages. The claims that follow seek to cover all suchpossibilities.

What is claimed is:
 1. An electrode and nozzle assembly for use with anelectrosurgical device comprising: a shroud including a distal portionand a proximal portion, a channel defining a longitudinal axis andextending between the distal portion and the proximal portion, thechannel being open at each end, and a port defining a lumen, the lumencommunicating with the channel, the longitudinal axis of the lumenintersecting the longitudinal axis of the channel to define an acuteangle; a conductive coating positioned on an internal wall of at least aportion of the channel and the lumen; an electrode positioned within thechannel, the electrode having a distal end extending from the distalportion of the shroud and a proximal end extending from the proximalportion of the shroud; and an end cap positioned adjacent the proximalportion of the shroud about the electrode, the end cap being overmoldedto the shroud and to the electrode.
 2. An electrode and nozzle assemblyas recited in claim 1, wherein the acute angle is between about 10degrees and about 20 degrees.
 3. An electrode and nozzle assembly asrecited in claim 2, wherein the acute angle is about 12.6 degrees.
 4. Anelectrode and nozzle assembly as recited in claim 1, wherein a recess isformed in the proximal portion of the shroud, the end cap beingpositioned within the recess.
 5. An electrode and nozzle assembly asrecited in claim 4, wherein at least a portion of the recess and atleast a portion of the end cap have a hexagonal configuration.
 6. Anelectrode and nozzle assembly as recited in claim 1, wherein a proximalend of the channel has a smaller diameter than the distal end of thechannel.
 7. An electrode and nozzle assembly as recited in claim 1,further including a dielectric tube positioned within the port.
 8. Anelectrode and nozzle assembly for use with an electrosurgical devicecomprising: a shroud including a distal portion and a proximal portion,the shroud defining a channel having a longitudinal axis and extendingbetween the distal portion and the proximal portion, the channel beingopen at each end; a conductive coating positioned on an internal wall ofat least a portion of the channel; and an electrode positioned withinthe channel, the electrode having a distal end extending from the distalportion of the shroud and a proximal end extending from the proximalportion of the shroud.